The Gulf of Mexico was in a giving mood throughout June, feeding a deep plume of tropical moisture to a succession of storm systems moving across Oklahoma. Not all areas were quite as fortunate as others, but a substantial portion of the state received significant, drought-reducing rainfall. The eastern Panhandle even got an unexpected boost from the remnants of hurricane Bud as it made its journey through the Gulf of California into the Northern Plains. The most prolific June rains fell from the eastern Panhandle through central and east central Oklahoma. Readings of 6-8 inches were common along that corridor with the Oklahoma City East Mesonet site leading the way at 8.74 inches. Beaver received 7.18 inches – nearly a third of their normal annual total – and 8.27 inches fell at Wilburton. Eighteen of the Mesonet’s 120 sites recorded at least 6 inches of rain and 40 reported at least 5 inches.
Significant deficits occurred along the periphery of the state. Areas along the Red River, the far northeast, and the western Panhandle fell 2-4 inches below normal. Ringling received a paltry 0.3 inch, while another 15 sites reported less than 2 inches. The statewide average was 4.07 inches according to preliminary data from the Mesonet, 0.45 inch below normal to rank as the 55th wettest June on record. Year-to-date rainfall remained quite variable, from more than 12 inches above normal in east central Oklahoma to 8-10 inches below normal in the southwest and northeast. The statewide average total of 16.96 inches for the first 6 months of 2018 was 2.07 inches below normal, the 56th driest January-June on record.
Despite the rainy weather, June was still on the hot side. According to preliminary data from the Oklahoma Mesonet, the statewide average temperature finished at 80.1 degrees, 3.6 degrees above normal to rank as the 15th warmest June on record. That lofty mark, combined with the warmest May in Oklahoma history, propelled the May-June period to the warmest on record as well at 77.5 degrees. The previous record of 77.4 degrees was set in 1911. The month’s highest temperature was 106 degrees, recorded at several Mesonet sites on three different dates. The combination of abundant rainfall, Gulf moisture and heat resulted in oppressive conditions at times. The Mesonet’s 120 stations recorded heat index values of at least 110 degrees 84 times during June, with a high of 114 degrees at Nowata on the 28th. Fifty-two of those readings occurred June 27-28. The Eva Mesonet site recorded the lowest temperature, 45 degrees, on June 3. The year thus far continued on the warm side with a statewide average of 56.8 degrees, a degree above normal to rank as the 27th warmest January-June on record.
Mother Nature made significant progress combating the drought during June, at least in the case of its severity. The percentage of the state in some level of drought actually increased by about 9 percent from the end of May, mostly across eastern Oklahoma. The portion in at least “severe” drought decreased, however, from 41 percent to 28 percent. “Exceptional” drought was virtually eliminated during June, down from 10 percent of the state to start the month. The Drought Monitor’s intensity scale slides from moderate-severe-extreme-exceptional, with exceptional being the worst classification.
The temperature and precipitation outlooks from the Climate Prediction Center (CPC) indicate the possibility of more hot, dry weather ahead. The maps for July show increased odds for above normal temperatures and below normal precipitation across the state. Unfortunately, that does not bode well for Oklahoma’s ongoing drought. CPC’s U.S. Monthly Drought Outlook for July sees drought persisting or intensifying where it already exists, with drought development “likely” across the rest of the state.